Gruff in appearance and not standing on protocol -- he was often seen in public with a cigarette in one hand until he quit smoking -- Van der Laan was known as a fearless and at times even biting manager, who was not afraid to speak his mind.

In one of his best-remembered moments, he snubbed President Vladimir Putin on a visit to the city in 2013, saying he was "too busy" to meet the Russian leader.

The mayor then had a rainbow flag flown from the city hall to protest Russia's policies against homosexuals.

- 'Amsterdam is weeping' -

His health took a turn for the worse in the last few months.

In one of his last public photos last month, a fragile-looking Van der Laan is supported at the arm by Dutch King Willem-Alexander after a visit to an inner-city suburb to talk to residents.

The #EberhardvanderLaan hashtag was the top trending topic on Twitter in the Netherlands, while flags across the country flew at half-mast on Friday.

A public farewell event will be held next Friday at a venue still to be disclosed, the ANP national news agency said.

Van der Laan is to be buried in a private ceremony next Saturday.

A lawyer by profession, Van der Laan started a campaign to tackle 600 of the city's most violent offenders and introduced a law against illegal squatters shortly after his appointment.

He was "a driven mayor who put his heart into the city and had a fervent belief that everyone counted in society," the King Willem-Alexander and Queen Maxima said on their Facebook page.

"I am deeply saddened by the death of Eberhard van der Laan... my good friend," European Commission President Jean-Claude Juncker.

"He was an incredible friend of Europe and a hugely popular mayor of his beloved Amsterdam," he said in a statement.

Dutch Prime Minister Mark Rutte said in a statement that "the news hit many people hard. Me too."

"Amsterdam is weeping for its mayor and so does the rest of the Netherlands," he said.